Randy F. Sweis, MD
Large phase III studies, such as the CHAARTED and STAMPEDE trials, have helped to significantly improved outcomes for men with prostate cancer, but unanswered questions remain, including what role immunotherapy could play in the treatment paradigm, said Randy F. Sweis, MD.
State of the Science Summit™, Sweis discussed recent progress and next steps in the prostate cancer paradigm.
OncLive: How has the treatment landscape of prostate cancer evolved in recent years?
: Prostate cancer is an interesting disease because numerous therapies have been FDA approved over the last few years. One of the areas in which it is most quickly evolving is the sequencing and timing of therapies. This has been an area of somewhat confusion, but we have also been able to make a significant impact on outcomes. Patients can live longer and have more time being in control of their cancer.
We are seeing this in large international studies such as CHAARTED or the STAMPEDE trial. That is where the most change is occurring. There are some efforts investigating things like immunotherapy in prostate cancer. That's been a challenging area, but there are a lot of people working on it and it has some potential in this field. We've seen a couple responders with immunotherapy; we just need a better understanding of the biology. This is an area where we can see some breakthrough in the next 5 years.
Are there any indications as to a patient population who might best respond to immunotherapy?
We don't know quite yet, especially in prostate cancer. How to select patients for this type of treatment is tricky, and it's something we definitely need more data for. We will hopefully see that in the next few years. It's an area of ongoing investigation.
We have some trials at our institution looking at combining a PARP inhibitor with an anti–PD-1 agent. This is a novel approach. There are others looking at the combination of ipilimumab (Yervoy) and nivolumab, which we've seen have promise in other cancer types. We have some hope here, and we'll see how it plays out. We've seen some responses, as I said before. It's just a matter of figuring out the right combination.
What are the remaining questions with regard to sequencing?
We have a lot of drugs now, especially those targeting the testosterone and androgen pathway. Several of them have shown success, and now there is a question of which one is optimal. Could these be combined with another therapy? Also, there is the chemotherapy question. Docetaxel given in the metastatic castrate-sensitive setting has been shown to improve survival. However, so has abiraterone. Some patients are receiving either one. This is going to be a big question. Which therapies should we be using upfront? We have to test them head to head.
The other question is of radium-223 dichloride (Xofigo). It's an infusion that targets bone metastases, and it's shown efficacy in castration-resistant patients. We have to see where this really fits in.
- Kyriakopoulos C, Chen Y, Carducci M, et al. Chemohormonal therapy in metastatic hormone-sensitive prostate cancer: long-term survival analysis of the randomized phase III E3805 CHAARTED Trial. J Clin Oncol. 2018;36(11):1080-1087. doi: 10.1200/JCO.2017.75.3657.
- James N, de Bono J, Spears M, et al. Abiraterone for prostate cancer not previously treated with hormone therapy. N Engl J Med. 2017;377:338-351. doi: 10.1056/NEJMoa1702900.
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